The Arctic Floe Edge Ecosystem

Key Insight

The narrative begins at the floe edge in Admiralty Inlet, northern Baffin Island, several miles out to sea, where firmness beneath feet belies the ordinary sense of being 'out to sea'. This unique environment, where Eskimo camps are established for narwhal hunting, presents a mix of elation and fear due to the exposure and the weather's potential capriciousness, even fatality. The danger of shifting ice is highlighted by an incident where a 5-square-mile ice sheet carrying a hunter and his companion was swept out of Admiralty Inlet towards Lancaster Sound, forcing a 12-hour journey across broken ice to firm shore.

This setting, despite its dangers, is teeming with life, characterized by the 'outcry of birds' and the 'bullet-whirr' of passing wings. Species like black-legged kittiwakes, northern fulmars, and black guillemots engage in 'weightless acrobatics' over zooplankton and arctic cod. On a 10-mile cliff between Baillarge Bay and Elwin Inlet, over 50,000 northern fulmars nest. Astonishingly, about one-third of the northwest Greenland population of 30 million dovekies pass over Lancaster Sound in May and June, showcasing the immense avian presence.

The floe edge is recognized as a rich biological crease, or 'ecotone,' a transitional area between different communities that charges border zones with evolutionary potential. This ecotone functions as a barrier in two planes: horizontally, for animals needing atmospheric oxygen to pass under the ice from the open sea, and vertically, as birds cannot penetrate the ice to feed underwater like guillemots. This ecosystem's foundation is 'epontic' algae growing on the bottom of the sea ice, which feed vast clouds of zooplankton. These, in turn, sustain arctic cod, which are prey for birds, narwhals, and ringed seals, with polar bears feeding on seals, and arctic foxes eventually on bears, demonstrating how the ice intricately holds this life together.